As in HTML 4 specification noted that :
ID and NAME tokens must begin with a letter ([A-Za-z]) and may be followed by any number of letters, digits ([0-9]), hyphens ("-"), underscores ("_"), colons (":"), and periods (".").
How can I validate an ID/NAME token is valid by using PHP?
I suppose a regular expression such as this one could do the trick :
^[A-Za-z][A-Za-z0-9_:\.-]*
For more informations, see the following section of the manual : Regular Expressions (Perl-Compatible)
And to use that, in PHP, you'd have to use the preg_match() function :
if (preg_match('/^[A-Za-z][A-Za-z0-9_:\.-]*/', $id)) {
// valid
}
Regular Expressions. /^[a-z]+[\w\_\-\:\.]*/i
Explanation:
/ #beginning of regular-expression
[a-z] #match any lowercase English letter
+ #match previous token one or more times
[\w\_\-\:\.] #match any word or digit, underscore, hyphen, colon or dot
* #match previous token zero or more times
/i #end regular expression with the i modifier, making it case-insensitive
With php you can use preg_match to get validation.
For more info on regular expressions, check out regular-expressions.info and GSkinner's regexp test